Potential and Kinetic EnergyPotential and Kinetic Energy

How is all energy divided?How is all energy divided?

PotentialEnergy

KineticEnergy

All Energy

GravitationPotentialEnergy

ElasticPotentialEnergy

ChemicalPotentialEnergy

What is Potential Energy?What is Potential Energy?

o Energy that is Energy that is stored and waiting stored and waiting to be used laterto be used later

What is Gravitational Potential What is Gravitational Potential Energy?Energy?

o Potential energy Potential energy due to an objectdue to an object’’s s positionposition

o P.E. = mass xP.E. = mass x height x height x

gravitygravityDon’t look down, Rover!

Good boy!

Calculate GPE!Calculate GPE!

What is the GPE of a girl who has a What is the GPE of a girl who has a mass of 40 kg and is standing on the mass of 40 kg and is standing on the edge of a diving board that is 5 m edge of a diving board that is 5 m above the water?above the water?

GPE=mgh GPE=mgh

What is Elastic Potential What is Elastic Potential Energy?Energy?

o Potential energy due compression Potential energy due compression or expansion of an elastic object.or expansion of an elastic object.

Notice the ball compressingand expanding

What is Chemical Potential What is Chemical Potential Energy?Energy?

o Potential energy Potential energy stored within the stored within the chemical bonds chemical bonds of an objectof an object

How Much Potential Energy?How Much Potential Energy?

Depends on height above the Earth Depends on height above the Earth and weight.and weight.

The higher it is, the more PE it hasThe higher it is, the more PE it has

The heavier it is, the more PE it hasThe heavier it is, the more PE it has

What is Kinetic Energy?What is Kinetic Energy?

o Energy an object has Energy an object has due to its motiondue to its motion

o K.E. = .5(mass x K.E. = .5(mass x speedspeed22))

How Much Kinetic Energy?How Much Kinetic Energy?

The faster an object moves, the more The faster an object moves, the more kinetic energy it has.kinetic energy it has.

Calculate KE!Calculate KE!

What is the kinetic energy of a girl What is the kinetic energy of a girl who has a mass of 40 kg and a who has a mass of 40 kg and a velocity of 3 m/s?velocity of 3 m/s?

KE=1/2mvKE=1/2mv2 2

Mechanical EnergyMechanical Energy

Energy possessed by an object due Energy possessed by an object due to its motion or position (the objects to its motion or position (the objects combined potential and kinetic combined potential and kinetic energy)energy)

ME=PE+KEME=PE+KE

Calculate!Calculate!A skateboarder has a PE of 200 A skateboarder has a PE of 200 joules due to his position at the top joules due to his position at the top of a hill and a kinetic energy of of a hill and a kinetic energy of

100 joules due to his 100 joules due to his

motion. What is his total motion. What is his total

mechanical energy?mechanical energy?

Law of Conservation of Law of Conservation of EnergyEnergy

No matter how energy is transferred No matter how energy is transferred or transformed, all of the energy is or transformed, all of the energy is still present somewhere in one form still present somewhere in one form or another. or another.

Skateboard RampSkateboard RampTop of skateboard ramp is 100% PE Top of skateboard ramp is 100% PE because gravity can pull him down but because gravity can pull him down but there is no velocity so no KEthere is no velocity so no KE

Going down the ramp PE is decreasing Going down the ramp PE is decreasing because elevation is decreasing but KE is because elevation is decreasing but KE is increasing because velocity increases increasing because velocity increases 50/5050/50

Bottom of ramp KE is 100% because Bottom of ramp KE is 100% because gravity cannot pull him down moregravity cannot pull him down more

ExamplesExamples

When on a rollercoaster, when do When on a rollercoaster, when do you have the maximum PE? KE?you have the maximum PE? KE?

When you climb a waterslide, what When you climb a waterslide, what type of energy are you gaining?type of energy are you gaining?

A lump of coal and a can of gasoline A lump of coal and a can of gasoline are examples of what type of are examples of what type of energy?energy?

More ExamplesMore Examples

Which is an example of the Which is an example of the conversion of PE to KE?conversion of PE to KE?

a.a.Catching a baseballCatching a baseball

b.b.Recharging your cell phone batteryRecharging your cell phone battery

c.c.Stretching a rubber bandStretching a rubber band

d.d.Coasting downhill on your bicycleCoasting downhill on your bicycle